An organic electroluminescence (hereinbelow, abbreviated to EL) element has been recently brought to attention as a light-emitting element. Research has been carried out on an organic EL display device using such an organic EL element, as an alternative to a liquid crystal display device (LCD), a CRT and other display devices. In particular, such an organic EL element has been brought to attention as a light-emitting element for realizing a thin display device. An example of such an organic EL display device is shown in FIG. 7.
As shown in FIG. 7, an organic EL display device 900 includes an organic EL panel 901. The organic EL panel 901 has an organic EL element 902 including a laminated structure, wherein an organic EL multilayer film 124 is sandwiched between an anode 144 and a cathode 911, the organic EL multilayer film containing an organic light-emitting compound. When a voltage is applied across the anode 144 and the cathode 911, holes and electrons are respectively injected from the anode 144 and from the cathode 911 into the organic EL multilayer film 124, and holes and electrons are recombined therein. Molecules of the organic light-emitting compound contained in the organic EL multilayer film 124 are excited by energy generated by the recombination. In the process wherein the excited molecules are deactivating to the ground state, light radiation is caused. The organic EL element 902 is an emissive element making use of this light radiation.
The organic EL multilayer film 124 contains at least an organic layer, which emits light by recombination of holes and electrons, which is called a light-emitting layer, and which has a single layer comprising a light-emitting layer or a multilayered structure containing a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer and the like as required.
In general, the organic EL panel 901 is fabricated by sequentially laminating, on a glass substrate 111, a transparent electrode made of, e.g., ITO (Indium Tin Oxide) to serve as the anode 144, the organic EL multilayer film 124 and an electrode made of, e.g., aluminum to serve as the cathode 911 so as to form the organic EL element 902 in an laminated structure; and hermetically disposing a concave opposed substrate 112 on the substrate 111 through a ultraviolet curing adhesive 113, the concave opposed substrate comprising a glass substrate and the like, the glass substrate covering the laminated structure.
The organic EL panel 901 has a circular polarizer 912 disposed on a viewer side surface thereof, the circular polarizer comprising a linear polarizer 921 and a ¼λ plate 922. External light, which comes into the organic EL panel 901, is prevented from being reflected on the electrodes to lower the contrast given by the organic EL display device 900. Specifically, the external light passes through the linear polarizer 921 of the circular polarizer 912 to be transformed into linearly polarized light, and the linearly polarized light is transformed into circularly polarized light by the ¼λ plate 922. The circularly polarized light is reflected by a surface of the cathode 911 after passing through the anode 144 as the transparent electrode and the organic EL multilayer film 124.
The reflected circularly polarized light passes through the ¼λ plate 922 to be transformed into linearly polarized light. The linearly polarized light has a polarizing direction substantially perpendicular to the polarization axis of the linear polarizer 921. For this reason, the external light reflected in the organic EL panel 901 cannot pass through the linear polarizer 921. Thus, external light, which comes into the organic EL panel 901, can be prevented from going out from a viewer side.
JP-A-2003-115383 discloses an example of an organic EL display device, which uses a polarizer to improve contrast. In the organic EL display device disclosed in this patent document, the polarizer, which is disposed on a light-emitting surface, absorbs external light, improving contrast.